This study is directed towards examining the specificity of pharmacologic agents acting on acetylcholinesterase, the structure of acetylcholinesterase, the molecular basis for its diversity and the biosynthesis and disposition of the multiple enzyme species. Pharmacologic specificity of various ligands will be examined by fluorescence techniques with the aim of delineating the specific sites and mechanisms by which therapeutic agents (anticholinesterases) and toxic substances organophosphate insecticides) inhibit or modulate acetylcholinesterase activity. In our ongoing studies on enzyme structure, the primary and secondary structures of the various enzyme forms (the hydrophobic dimer of 5.6S and the elongated (17+13)S species) will be elucidated through protein sequencing and c-DNA isolation and its sequencing. Nuclei acid sequencing should yield the overall sequence but the protein sequencing will be necessary to define the active center serine where irreversible inhibitors act, the enzyme surface giving rise to the peripheral anionic site, sites of oligosaccharide conjugation, the major antigenic sites to which monoclonal antibodies are directed, the hydrophobic sequence responsible for membrane association of the 5.6S form, intra and intersubunit disulfide bonds and the peptides that distinguish the catalytic subunits in the various molecular forms. Since the structure of the gene products can be well defined in Torpedo, this information will be applied to a detailed study of the biosynthesis of the individual nascent chains of the enzyme forms, the m-RNA species active in translating acetylcholinesterase, the regulation of assembly of subunits and the posttranslational processing steps which give rise to active enzymes. Specifically, we hope to ascertain if separate genes control the biosynthesis of the catalytic subunits of the various molecular forms of the enzyme, whether processing of alternative m-RNA can be distinguished, and how the processes of subunit assembly and glycosylation influence expression of the final gene product.